With the global population exploding at around 7 billion and around 2.6 billion people not having access to usable water, a major global crisis may be looming. According to a November 2006 L.A. Times article, dirty water is becoming a leading cause of infant death globally, and may be responsible for the deaths of up to 1.8 million children under age 5. Global water use may also be increasing faster than population growth, and global water demands are expected to increase by up to 40% in this decade. It is believed that up to two-thirds of the world may experience water scarcity by 2025, and some countries may be on the verge of crippling demographic crisis from shortage of clean water.
One way of addressing water scarcity is treating and reusing municipal water, since much of it is typically lost as wastewater. Such wastewater can also cause environmental problems, including pollution of scarce fresh water sources into which the wastewater often ends up. There are many processes and systems for treating wastewater and reclaiming the treated water for irrigation and reuse in various ways. However, many effective approaches can require electric power, which is another commodity that may not be readily available and/or may be costly in many developing nations. Solar powering of such systems can provide the power required for daytime operation. However, two challenges relating to solar powering include (i) how to keep the cost of solar arrays and their ancillaries economical relative to the water treatment plant cost, and (ii) how to perform treatment during darkness periods, also at reduced or minimum cost. It would also be helpful for such a solar powered system to require relatively little electric power to operate.
A wastewater biotreatment system that performs all its treatment in a Single Vessel Multi-zone Bioreactor (SVMB) has electrical requirements. Such a system is described in U.S. Pat. No. 7,008,538, and may refer to a single vessel biotreatment system that has a blower for aeration and a gearbox motor for its sludge rake. If the wastewater is not being fed by gravity, then a feed pump can be used for delivering the influent into the bioreactor and add to the electrical load. Such a system can be powered by a solar panel during daytime, and can operate over the electric grid at nighttime. However, such solar powering may not be economical in terms of the initial cost of the solar panel, which would require being oversized to accommodate starting currents that can range up to six times the running current for single phase motors and up to 3 times the running currents for three phase motors. Furthermore, a main load of the system, the aeration blower, would typically operate near its full design output a majority of the time. Thus, reducing or minimizing the electric load requirements can in turn reduce or minimize the size and cost of the solar panel that would be required for solar powering, and the electrical grid powering costs when the system is operating off the electric grid.
Also, a solar-grid powering approach may not be implementable in all circumstances. For example, in many parts of the world, there may be a scarcity of electric power and/or power interruptions during daytime and/or after darkness. In many villages and work camps, as an example, there may be no grid source electricity, and basics are sometimes met through the use of costly electric generators that may continuously require fuel and routine maintenance. Accordingly, one solution for the above single vessel biotreatment system (in both areas without adequate electric grid power as well as other areas) is for the water reclamation plant to be self-sustaining. Full reliance on batteries in darkness periods may be possible, but the size/quantity of such batteries that would be needed to power practical size water reclamation plants may be cumbersome and/or prohibitive in cost.
Some previous patents and publications may not provide solutions towards meeting the above problems. For example, U.S. Patent Application Publication No. 2011/0146751 (McGuire et al.) relates to a non-self-sustaining traditional solar power system with battery storage or generators. In particular, it relates to providing a mobile solar power station for providing electricity to living and working and powering a related drinking water filtration system, ventilation system and telecommunications equipment.
U.S. Patent Application Publication No. 2012/097590 (Early et al.) generally relates to a wastewater treatment system within a cylindrical storage vessel, using an electromagnetic precipitator approach that removes particles and chemicals for treating the liquid. It describes biological reduction of BOD-5 (Biochemical Oxygen Demand Over 5 Days) from wastewater, as well as COD (Chemical Oxygen Demand), Nitrates and Phosphorus and treating sludge.
U.S. Patent Application Publication No./152829 (Henderson et al.) generally discusses various generic wastewater treatment processes and a method for treating wastewater that includes capturing oxygen and carbon dioxide to promote the growth of algae contained within the wastewater treatment system, which may contribute to eutrophication in water bodies where the treated wastewater is discharged. Eutrophication can have negative environmental effects, including reductions in fish life and other life-forms.
U.S. Patent Application Publication No. 2012/0234769 (Bitterson) generally relates to plasma-based devices, systems and methods wherein non-thermal plasmas can be employed for treatments of liquids or liquid streams for the removal or modification of chemical contaminants, such as arsenic.
U.S. Pat. No. 6,798,080 (Baarman et al.) generally relates to method of generating electrical power from water filtration systems by the water operating a turbine and generator for producing electricity.
U.S. Pat. No. 7,850,848 (Limacaco) generally describes a ‘self-sustaining’ wastewater treatment facility that abates greenhouse gas abatement to capture CO2 and produce biomass to address environmental needs. The treatment facility can include an array of rotating media wheels that create an ordered mixing of algae for sustained growth. The biomass that may be collected from the rotating media wheels can be used for other processing, such as producing bio-fuels. The system can be expanded to fuel further algal growth.
U.S. Pat. No. 8,216,471 (Ren et al.) generally relates to a bioreactor for treatment of concentrated organic wastewater. The process of treatment may rely on a moving bed bioreactor (MBBR) and an upflow of anaerobic sludge using the same. The bioreactor can include an inner layer and an outer layer, in which the inner layer can be an upflow anaerobic sludge blanket (UASB) and the outer layer can be a moving bed biofilm reactor (MBBR).
German patent document DE 195 20 733 (Heinz et al.) generally pertains to a botanical water treatment plant that can include a gas-tight vessel located within a water effluent collection shaft that receives effluent water in batches from a storage vessel. Ventilation shafts within the gas-tight vessel can be linked to a compressor by a pipe and valve. Water can be transferred from layers above the sludge into a botanical filter bed. The compressor can be electrically-powered, deriving power from the mains, wind, or solar energy.
Japanese patent document 2006-218383 (Toshiya) generally relates to high water content organic waste treatment systems including a latent heat recovering vacuum dryer, which can dry dehydrated cakes that have high water content organic waste. A waste heat recovery portion of the system can employ a boiler for generating steam and driving a turbine, etc. Also, Japanese patent document 11-50509 (Koji et al) generally discusses solar powering of a flush toilet for remote areas with a simple solar panel.